Chain operator for windows

Abstract: An operator for a window has a chain (2) as an operating member, a sprocket wheel (4) for advancing and retracting the chain (2), and a counterbalancing spring (5) operatively connected to a shaft (9) of the sprocket wheel (4).

Description: The present invention relates to an operator for opening and closing a window having a main frame and a sash mounted for pivotal movement relative to the main frame between a closed position and any position within a range of ventilating positions, the sash being mounted in such a way that a substantial component of its weight will force the window towards said closed position, said operator comprising: a housing designed for mounting on a frame member of the main frame; a flexible operating member positioned in said housing and having an end adapted to be connected to the sash; and drive means including a movable part engaging said flexible operating member for moving it between a retracted position in which said flexible operating member is entirely accommodated in the housing and any of a number of projecting positions in which the flexible operating member projects from the housing, said retracted position corresponding to the closed position and said projecting positions corresponding to the ventilating positions of the window. Manually-operated and power-driven operators are known for moving a window between closed and open positions, for example, a window having a stationary main frame mounted in a roof of a house or other building, especially a sloped roof, and a sash hinged to the main frame at the top of the sash for pivoting toward and away from the main frame. Such operators are typically mounted on a bottom member of the main frame and connected to a bottom member of the sash for pushing the sash away from the main frame and drawing the sash into engagement with the main frame. When the window operator is actuated to move the window in an opening direction, it must overcome a component of the weight of the window, especially when the window is mounted in a roof. A chain operator for such a window, and disclosing the features of the preamble of claim 1, is disclosed in US-A-4. 521,993 issued to Tacheny et al. Another window operator is known from US-A-4,481,735 which is considered the most relevant state of the art to the present invention. For chain-operated automobile windows, which are vertically slidable from an open position in which the pane is retracted in a door or carbody part subjacent to the window opening it is known e.g. from US-A-1,563,115 to assist the lifting movement of the pane towards the closed position by a counterbalancing spiral spring arranged in connection with the chain drive mechanism. Moreover, US-A-2,698,173, US-A-5,097,629 and US-A-5,179,803 discloses various designs of lift-assisting counterbalancing means for building windows including roof windows with socalled sash operators having rigid operating members. Against this prior art it is the object of the present invention to offer a simple and compact construction of a window operator typically for a roof or skylight window having a flexible operating member, such as a chain opener and provided with lift-assisting counterbalancing means without detracting from the compact design. According to the invention a window operator of the kind defined is characterized in that counterbalancing means positioned entirely within the housing is provided for counterbalancing said weight component, said counterbalancing means comprising a tension spring one end of which is connected with a stationary wall of the housing, whereas the other end is operatively connected with the movable part of said drive means via a flexible member guided in the housing by a guide member to a connection on a shaft of the drive means to provide a counterbalancing force in the direction of movement of said flexible operating member from the retracted position towards said projecting positions so as to transmit to said flexible operating member a force acting to facilitate movement of the window against its weight from said closed position to said ventilating position. Fig. 1 is a top side view of the operator unit according to the present invention with a cover of the housing removed; Fig. 2 is an enlarged view of a section of the chain of the operator unit of Fig. 1; Fig. 3 is a side view of the section of chain in the direction of arrows III in Fig. 2; Fig. 4 is an enlarged view of the sprocket wheel of the operator of Fig. 1; Fig. 5 is an enlarged top view of the sprocket wheel and shaft of Fig. 1; Fig. 6 is a cross-section showing engagement between the sprocket wheel and a rivet of the chain; Fig. 7 is a perspective view of the operator according to the present invention and a manual drive unit aligned with the sprocket wheel shaft, showing the cover of the housing removed and lying in a horizontal orientation; Fig. 8 is a perspective view of an alternate, electric drive unit; and Figs. 9 and 10 show two alternative embodiments of the operator unit. As can best be seen from Fig. 1, an operator housing 1 is designed for mounting on a frame member of the main frame of a pivotally opening window opposite to the pivot axis of the main frame, e.g., at the bottom frame member of a main frame of a tophinged window, in particular a window designed for installation in an inclined roof surface. The housing 1 accommodates a flexible operating member designed as a chain 2 or chain-like member guided by guide rails 20 to 24. One end of the chain 2 is designed to extend outside the housing 1 for releasable or permanent coupling to the corresponding member of the sash of the window, e.g., the bottom sash member of the sash of the window. Inside the housing 1, the chain 2 is in operative connection with a drive means being a drive wheel forming a sprocket wheel 4 for the chain, the sprocket wheel being rotatably mounted in the housing. As easily appreciated, clockwise rotation of wheel 4 in Fig. 1 will move the chain 2 in the direction of opening the window. The arrangement is counterbalanced by a tension spring 5, one end 5a of which is secured at the end of an extension 6 of the housing 1, whereas the other end 5b is connected through a flexible member 7 like a wire or cord guided in the housing by a guide member 8 to a connection on a shaft 9 of the wheel 4 in a manner to assist the clockwise rotation of the wheel 4, thereby facilitating the opening movement of the window by compensating for the weight of the window. In order to adapt the counterbalancing spring arrangement to different window sizes and/or roof inclinations, adjusting means for adjusting the tension of spring 5 may be provided at the end 5a of the spring, e.g., in the manner illustrated in Fig. 10 and explained below. The flexible member 7 is connected to and wound around the shaft 9, so that the flexible member winds up on the shaft as the window moves in a closing direction and unwinds as the window moves in an opening direction. The tension spring 5 is entirely within the housing 1 and defines a longitudinal axis which is stationary in all positions of the window. As seen in Figs. 5, 7 and 8, the shaft 9 of the wheel 4 terminates in a pin 10 of a non-circular, e.g. hexagonal, cross-section, which may cooperate either with a manual drive unit 11 operated by a handle 12, e.g. a crank, or with a motor drive unit 13. In Fig. 7, a cover 1a for the housing 1 is shown removed and lying in front of the housing. As seen in Figs. 2, 3 and 6, the chain 2 is composed of chain members 14 of a substantially L-shaped cross-section providing an edge flange 15. Members 14 are interconnected by chain links 16 by means of rivets 17 or the like forming pivotal joints between members and links 16. This structure provides improved strength and rigidity to chain 2 so that it will only deflect in the direction illustrated in Figs. 1 and 7. The chain 2 exerts a force on the sash of the window when said chain is under a compressive load applied along the longitudinal axis of the chain. Rivets 17 protrude to one side of the chain 2 to engage with curved recesses 18 in the circumference of the sprocket wheel 4, as can be seen from Figs. 3 and 6. Since the movement of the window sash from the closed position to a sufficiently open position may require displacement of a considerable length of chain 2 out of housing 1 and, thereby, a considerable number of revolutions of sprocket wheel 4 and shaft 9, if the operative diameter of the sprocket wheel 4 is to be kept within acceptable limits with regard to the dimensions of housing 1, the corresponding length of movement of spring end 5b between the tensioned condition and the tension relieved condition may require a substantial length of spring 5 and corresponding dimensions of extension 6 of housing 1. In order to minimize this design restraint, alternative embodiments of the counterbalancing spring arrangement may be provided as illustrated in Figs. 9 and 10, in which elements corresponding to those of Fig. 1 have been given the same reference numerals. In Fig. 9, the counterbalancing spring arrangement comprises two separate tension springs 25 and 26 connected in series by means of a flexible member 27 like a wire or a cord which is bent or curved 180 degrees over a guide member 28 so that the separate spring sections 25 and 26 extend in parallel overlying relationship. Thereby, the length of extension 6 of housing 1 can be significantly reduced compared to what would otherwise be required if a single linear spring were used. The same result may be achieved by an arrangement as illustrated in Fig. 10, in which two separate springs 29 and 30 are connected in parallel with one end of each spring connected to a common disc or flange member 31 which is displaceable in extension 6 by means of an adjusting screw 32 having a portion projecting out of the extension 6, whereas the other end of each spring is connected with the wire or cord 7 via a common coupling disc or flange 33. It will be apparent to those skilled in the art and it is contemplated that variations and/or changes in the embodiments illustrated and described herein may be made without departure from the present invention.

Claims: An operator for opening and closing a window having a main frame and a sash mounted for pivotal movement relative to the main frame between a closed position and any position within a range of ventilating positions, the sash being mounted in such a way that a substantial component of its weight will force the window towards said closed position, said operator comprising: a housing (1) designed for mounting on a frame member of the main frame; a flexible operating member (2) positioned in said housing (1) and having an end adapted to be connected to the sash; and drive means (4) including a movable part engaging said flexible operating member for moving it between a retracted position in which said flexible operating member (2) is entirely accommodated in the housing (1) and any of a number of projecting positions in which the flexible operating member (2) projects from the housing (1), said retracted position corresponding to the closed position and said projecting positions corresponding to the ventilating positions of the window; characterized in that counterbalancing means (5) positioned entirely within the housing (1) is provided for counterbalancing said weight component, said counterbalancing means comprising a tension spring (5) one end (5a) of which is connected with a stationary wall of the housing (1), whereas the other end (5b) is operatively connected with the movable part of said drive means via a flexible member (7) guided in the housing (1) by a guide member (8) to a connection on a shaft (9) of the drive means (4) to provide a counterbalancing force in the direction of movement of said flexible operating member (2) from the retracted position towards said projecting positions so as to transmit to said flexible operating member (2) a force acting to facilitate movement of the window against its weight from said closed position to said ventilating position. An operator as claimed in claim 1, characterized in that said flexible operating member is a chain (2) and the movable part of said drive means for moving said flexible operating member comprises a rotatable sprocket wheel (4) mounted in said housing (1), said rotatable sprocket wheel (4) engaging said chain (2). An operator as claimed in claim 2, characterized in that said rotatable sprocket wheel (4) has a shaft (9), said shaft having means for coupling said shaft to a drive unit (11,13). An operator as claimed in claim 3, characterized in that said drive unit is a manual drive unit (11). An operator as claimed in any of the preceding claims, characterized in that said one end (5a) of the spring (5) is connected with said stationary wall of the housing (1) via adjusting means for adjusting the spring tension. An operator as claimed in any of the preceding claims, characterized in that said counterbalancing spring means comprises two separate series connected spring sections (25,26) extending in overlying parallel relationship. An operator as claimed in any of claims 1 to 5, characterized in that said counterbalancing spring means comprises two separate spring sections (29,30) connected in parallel. An operator as claimed in claim 3, characterized in that said drive unit is an electric drive unit (13). An operator as claimed in claim 2, characterized in that said chain comprises alternating chain members (14) and links (16), and rivets (17) interconnecting said chain member (14) and said links (16), said rivets (17) having projecting ends, said rotatable sprocket wheel (4) engaging said projecting ends. An operator as claimed in any of the preceding claims, characterized in that said counterbalancing spring means axis has a stationary axis.

Inventors: LINDGREN CLAES, LINDGREN, CLAES
Applicants: VELUX IND AS, VELUX INDUSTRI A/S
Application year: 1994
Main classification: E05F11
IPC codes: E05F11, F16G13